Signaling pathways and microRNAs, the orchestrators of NANOG activity during cancer induction

Association of CD133, ALDH1, CD117 and OCT4 expression with prognosis of patients with cervical cancer

Cancer stem cells (CSC), a small population of neoplastic cells, are associated with worse prognosis. The aim of this study was to evaluate the expression of ALDH1, CD117, CD133 and OCT4; potential markers of CSC; and their associations with the prognosis of women diagnosed with cervical cancer. This retrospective cohort study included 126 women diagnosed with cervical cancer whose biopsies were analyzed by immunohistochemistry. Median values of marked cells were used to define cutoff points for low and high expression. For specific survival, multivariate analyses showed statistical significance for lymph node metastases (HR 8.15; 95% CI 3.00-22.18) and borderline significance for high CD133 expression (p = 0.058). For overall survival, multivariate analyses showed statistical significance for IIA-IVB staging (HR 4.60; 95% CI 1.46-14.56), lymph node metastases (HR 5.13; 95% CI 12.02-13.03) and high CD133 expression (2.67; 95% CI 1.11-6.43). Considering only women with SCC, the same clinicopathological variables were associated with worse specific and overall survival in univariate analyses. However, higher expression of CD 133 (HR 11.10; 95% CI 2.42-50.94 and 6.00; 95% CI 2.02-17.87) and staging IIA-IVB (HR 5.96; 95% CI 1.30-27.34 and HR 12.47; 95% CI 2.45-63.54) respectively impacted negatively specific and overall survival, as multivariate analyses showed. Secondarily, it was observed that ALDH1 expression was associated with adenocarcinoma and CD117 expression with squamous cells carcinoma. Higher expression of CD133 was associated with worse specific and overall survival, indicating that it could have relevance as a clinical marker and therapeutic target.

Selected markers of ovarian cancer and their relation to targeted therapy (Review)

Despite advances in surgical treatment techniques and chemotherapy-including anti-angiogenic and immune poly (ADP-ribose) polymerase inhibitors, the 5-year survival rate in ovarian cancer (OC) remains low. The reasons for this are the diagnosis of cancer in advanced clinical stages, chemoresistance and cancer recurrence. New therapeutic approaches are being developed, including the search for new biomarkers that are also targets for targeted therapy. The present review describes new molecular markers with relevance to targeted therapy, which to date have been studied only in experimental research. These include the angiogenic protein angiopoietin-2, the transmembrane glycoprotein ectonucleotide pyrophosphatase/phosphodiesterase 1, the adhesion protein E-cadherin, the TIMP metallopeptidase inhibitor 1 and Kruppel-like factor 7. Drugs affecting cancer stem cells (CSCs) in OC, such as metformin and salinomycin, as well as inhibitors of CSCs markers aldehyde dehydrogenase 1 (with the drug ATRA) and the transcription factor Nanog homeobox (microRNA) are also discussed. A new approach to prevention and possible therapies under investigation such as development of vaccines containing a subpopulation of CD117(+) and CD44(+) stem cells with a promising option for use in women with OC was described.

Transcriptional regulation of cancer stem cell: regulatory factors elucidation and cancer treatment strategies

Cancer stem cells (CSCs) were first discovered in the 1990s, revealing the mysteries of cancer origin, migration, recurrence and drug-resistance from a new perspective. The expression of pluripotent genes and complex signal regulatory networks are significant features of CSC, also act as core factors to affect the characteristics of CSC. Transcription is a necessary link to regulate the phenotype and potential of CSC, involving chromatin environment, nucleosome occupancy, histone modification, transcription factor (TF) availability and cis-regulatory elements, which suffer from ambient pressure. Especially, the expression and activity of pluripotent TFs are deeply affected by both internal and external factors, which is the foundation of CSC transcriptional regulation in the current research framework. Growing evidence indicates that regulating epigenetic modifications to alter cancer stemness is effective, and some special promoters and enhancers can serve as targets to influence the properties of CSC. Clarifying the factors that regulate CSC transcription will assist us directly target key stem genes and TFs, or hinder CSC transcription through environmental and other related factors, in order to achieve the goal of inhibiting CSC and tumors. This paper comprehensively reviews the traditional aspects of transcriptional regulation, and explores the progress and insights of the impact on CSC transcription and status through tumor microenvironment (TME), hypoxia, metabolism and new meaningful regulatory factors in conjunction with the latest research. Finally, we present opinions on omnidirectional targeting CSCs transcription to eliminate CSCs and address tumor resistance.

A comprehensive review of lncRNA CRNDE in cancer progression and pathology, with a specific glance at the epithelial-mesenchymal transition (EMT) process

It has been suggested that the long non-coding RNAs (lncRNAs), such as colorectal neoplasia differentially expressed (CRNDE), may contribute to the formation of human cancer. It is yet unknown, though, what therapeutic significance CRNDE expression has for different forms of cancer. CRNDE has recently been proposed as a possible diagnostic biomarker and prognostic pred for excellent specificity and sensitivity in cancer tissues and plasma. To provide the groundwork for potential future therapeutic uses of CRNDE, we briefly overview its biological action and related cancer-related pathways. Next, we mainly address the impact of CRNDE on the epithelial-mesenchymal transition (EMT). The epithelial-mesenchymal transition, or EMT, is an essential biological mechanism involved in the spread of cancer.

Nanog, as a key cancer stem cell marker in tumor progression

Cancer stem cells (CSCs) are a small population of malignant cells that induce tumor onset and development. CSCs share similar features with normal stem cells in the case of self-renewal and differentiation. They also contribute to chemoresistance and metastasis of cancer cells, leading to therapeutic failure. To identify CSCs, multiple cell surface markers have been characterized, including Nanog, which is found at high levels in different cancers. Recent studies have revealed that Nanog upregulation has a substantial association with the advanced stages and poor prognosis of malignancies, playing a pivotal role through tumorigenesis of multiple human cancers, including leukemia, liver, colorectal, prostate, ovarian, lung, head and neck, brain, pancreatic, gastric and breast cancers. Nanog through different signaling pathways, like JAK/STAT and Wnt/β-catenin pathways, induces stemness, self-renewal, metastasis, invasiveness, and chemoresistance of cancer cells. Some of these signaling pathways are common in various types of cancers, but some have been found in one or two cancers. Therefore, this review aimed to focus on the function of Nanog in multiple cancers based on recent studies surveying the suitable approaches to target Nanog and inhibit CSCs residing in tumors to gain favorable results from cancer treatments.

Anti-Cancer Effects of Dietary Polyphenols via ROS-Mediated Pathway with Their Modulation of MicroRNAs

Consumption of coffee, tea, wine, curry, and soybeans has been linked to a lower risk of cancer in epidemiological studies. Several cell-based and animal studies have shown that dietary polyphenols like chlorogenic acid, curcumin, epigallocatechin-3-O-gallate, genistein, quercetin and resveratrol play a major role in these anticancer effects. Several mechanisms have been proposed to explain the anticancer effects of polyphenols. Depending on the cellular microenvironment, these polyphenols can exert double-faced actions as either an antioxidant or a prooxidant, and one of the representative anticancer mechanisms is a reactive oxygen species (ROS)-mediated mechanism. These polyphenols can also influence microRNA (miR) expression. In general, they can modulate the expression/activity of the constituent molecules in ROS-mediated anticancer pathways by increasing the expression of tumor-suppressive miRs and decreasing the expression of oncogenic miRs. Thus, miR modulation may enhance the anticancer effects of polyphenols through the ROS-mediated pathways in an additive or synergistic manner. More precise human clinical studies on the effects of dietary polyphenols on miR expression will provide convincing evidence of the preventive roles of dietary polyphenols in cancer and other diseases.

siRNA-mediated silencing of Nanog reduces stemness properties and increases the sensitivity of HepG2 cells to cisplatin

Liver cancer is one of the most lethal cancers having worldwide prevalence. Despite significant progress in cancer therapy, liver cancer-induced mortality is very high. Nanog, as an essential transcription factor modulating cellular multipotency, causes tumor progression, drug resistance, and preserves stemness properties in various tumors such as liver cancer. Thus, this research was conducted to evaluate the impact of combination therapy of Nanog siRNA/cisplatin on the sensitivity of liver cancer cells to this drug. HepG2 cells were transfected with Nanog siRNA and treated with cisplatin, individually and in combination. Then, it was observed that in transfected HepG2 cells, Nanog expression was significantly reduced at mRNA level and also these cells were sensitized to cisplatin. In addition, to assess the impact of Nanog siRNA and cisplatin individually and in combination on cells' viability, migration capacity, apoptosis, and cell cycle progression, the MTT, wound healing, colony formation assay, Annexin V/PI staining, and flow cytometry assays were applied on HepG2 cells, respectively. Also, the quantitive Real-Time PCR was used to check the expression of stemness-associated genes (CD44, CD133, and Sox2), and apoptosis-related genes (caspase-3, 8, 9, BAX and Bcl2) after combination therapy. It is indicated that the combination of Nanog siRNA and cisplatin significantly reduced proliferation, migration, and colony formation ability, as well as increased apoptosis rate, and cell cycle arrest. Also, it is found that the combination of Nanog siRNA and cisplatin down-regulated the expression of stemness-associated genes and up-regulated apoptosis-related genes in HepG2 cells. Hence, it can be suggested that Nanog inhibition in combination with cisplatin is a potential therapeutic strategy for developing new therapeutic approaches for liver cancer.

Hepatitis B and Hepatitis C Virus Infection Promote Liver Fibrogenesis through a TGF-β1-Induced OCT4/Nanog Pathway

Hepatitis B virus (HBV)/hepatitis C virus (HCV) coinfection accelerates liver fibrosis progression compared with HBV or HCV monoinfection. Octamer binding transcription factor 4 (OCT4) and Nanog are direct targets of the profibrogenic TGF-β1 signaling cascade. We leveraged a coculture model to monitor the effects of HBV and HCV coinfection on fibrogenesis in both sodium taurocholate cotransporting polypeptide-transfected Huh7.5.1 hepatoma cells and LX2 hepatic stellate cells (HSCs). We used CRISPR-Cas9 to knock out OCT4 and Nanog to evaluate their effects on HBV-, HCV-, or TGF-β1-induced liver fibrogenesis. HBV/HCV coinfection and HBx, HBV preS2, HCV Core, and HCV NS2/3 overexpression increased TGF-β1 mRNA levels in sodium taurocholate cotransporting polypeptide-Huh7.5.1 cells compared with controls. HBV/HCV coinfection further enhanced profibrogenic gene expression relative to HBV or HCV monoinfection. Coculture of HBV and HCV monoinfected or HBV/HCV coinfected hepatocytes with LX2 cells significantly increased profibrotic gene expression and LX2 cell invasion and migration. OCT4 and Nanog guide RNA independently suppressed HBV-, HCV-, HBV/HCV-, and TGF-β1-induced α-SMA, TIMP-1, and Col1A1 expression and reduced Huh7.5.1, LX2, primary hepatocyte, and primary human HSC migratory capacity. OCT4/Nanog protein expression also correlated positively with fibrosis stage in liver biopsies from patients with chronic HBV or HCV infection. In conclusion, HBV and HCV independently and cooperatively promote liver fibrogenesis through a TGF-β1-induced OCT4/Nanog-dependent pathway.

Autophagy regulates the cancer stem cell phenotype of head and neck squamous cell carcinoma through the noncanonical FOXO3/SOX2 axis

Autophagy is an essential catabolic process that orchestrates cellular homeostasis and plays dual roles in tumor promotion and suppression. However, the mechanism by which autophagy affects the self-renewal of cancer stem cells (CSCs) remains unclear. In this study, we investigated whether autophagy activation contributes to CSC properties of head and neck squamous cell carcinoma (HNSCC). The results showed that the autophagy level and CSC properties of HNSCC cells were elevated in response to several adverse conditions, including treatment with cisplatin, starvation, and hypoxia. Pretreatment with autophagy inhibitors, such as 3-MA and chloroquine, diminished the CSC properties acquired under adverse conditions. In addition, the isolated CSCs were endowed with stronger autophagic activity than non-CSCs, and the CSC properties were dampened when autophagy was inhibited either by 3-MA, chloroquine, or Beclin1 knockdown. Notably, the tumor-initiating activity of CSCs was decreased upon knocking down Beclin1. Further study revealed that FOXO3, a substrate for autophagy, was enriched in the nucleus of cells with lower autophagy levels. Nuclear FOXO3 directly bound to the promoter region of SOX2 and negatively regulated its transcriptional activity. Overexpression of FOXO3 decreased the expression of SOX2 and thereby impaired the CSC phenotype both in vitro and in vivo. Taken together, our findings suggest that the activation of autophagy is essential for the acquisition of CSC properties in adverse conditions and the self-renewal of CSCs. We clarify the role of autophagy in regulating the CSC phenotype and demonstrate that the noncanonical FOXO3/SOX2 axis is the intrinsic regulatory mechanism.

Therapeutic potential of AMPK signaling targeting in lung cancer: Advances, challenges and future prospects

Lung cancer (LC) is a leading cause of death worldwide with high mortality and morbidity. A wide variety of risk factors are considered for LC development such as smoking, air pollution and family history. It appears that genetic and epigenetic factors are also potential players in LC development and progression. AMP-activated protein kinase (AMPK) is a signaling pathway with vital function in inducing energy balance and homeostasis. An increase in AMP:ATP and ADP:ATP ratio leads to activation of AMPK signaling by upstream mediators such as LKB1 and CamKK. Dysregulation of AMPK signaling is a common finding in different cancers, particularly LC. AMPK activation can significantly enhance LC metastasis via EMT induction. Upstream mediators such as PLAG1, IMPAD1, and TUFM can regulate AMPK-mediated metastasis. AMPK activation can promote proliferation and survival of LC cells via glycolysis induction. In suppressing LC progression, anti-tumor compounds including metformin, ginsenosides, casticin and duloxetine dually induce/inhibit AMPK signaling. This is due to double-edged sword role of AMPK signaling in LC cells. Furthermore, AMPK signaling can regulate response of LC cells to chemotherapy and radiotherapy that are discussed in the current review.

Interplay between SOX9 transcription factor and microRNAs in cancer

SOX transcription factors are critical regulators of development, homeostasis and disease progression and their dysregulation is a common finding in various cancers. SOX9 belongs to SOXE family located on chromosome 17. MicroRNAs (miRNAs) possess the capacity of regulating different transcription factors in cancer cells by binding to 3'-UTR. Since miRNAs can affect differentiation, migration, proliferation and other physiological mechanisms, disturbances in their expression have been associated with cancer development. In this review, we evaluate the relationship between miRNAs and SOX9 in different cancers to reveal how this interaction can affect proliferation, metastasis and therapy response of cancer cells. The tumor-suppressor miRNAs can decrease the expression of SOX9 by binding to the 3'-UTR of mRNAs. Furthermore, the expression of downstream targets of SOX9, such as c-Myc, Wnt, PI3K/Akt can be affected by miRNAs. It is noteworthy that other non-coding RNAs including lncRNAs and circRNAs regulate miRNA/SOX9 expression to promote/inhibit cancer progression and malignancy. The pre-clinical findings can be applied as biomarkers for diagnosis and prognosis of cancer patients.